Heritabilities of somatotype components in a population from rural Mozambique

Abstract

There have been few genetic studies of normal variation in body size and composition conducted in Africa. In particular, the genetic determinants of somatotype remain to be established for an African population. (1) To estimate the heritabilities of aspects of somatotype and (2) to compare the quantitative genetic effects in an African population to those that have been assessed in European and American populations. The sample composed of 329 subjects (173 males and 156 females) aged 7-17 years, belonging to 132 families. The sibships in the sample ranged in size from two to seven individuals. All sampled individuals were residents of the Calanga region, an area located to the north of Maputo in Mozambique. Somatotype was assessed using the Heath-Carter technique. Herit abilities were estimated using SAGE software. Moderate heritabilities were determined for each trait. Between 30 and 40% of the variation in each somatotype measure was attributable to genetic factors. The heritability of ectomorphy was 31%. Mesomorphy was similarly moderately heritable, with approximately 30% of the variationattributable to genetic factors. The heritability of endomorph was higher in the Calanga population (h(2) = 0.40). Quantitative genetic analyses of somatotype variation among siblings indicate that genetic factors significantly influence endomorphy, mesomorhpy, and ectomorphy. However, environmental factors also have significant effects on the variation in physique present in the population of Calanga. Lack of proper nutrition, housing, medical assistance, and primary health care, together with very demanding and sex-specific daily chores may contribute to the environmental effects on these traits.

Genetics of somatotype and physical fitness in children and adolescents

“…A Portuguese family study reported a resemblance in somatotype components within siblings, indicating the effect of familial factors but did not report heritability estimates (Pereira et al, 2017). A Canadian family study reported heritability estimates varying between 0.56 and 0.64 (Katzmarzyk et al, 2000) whereas a family study from rural Mozambique reported lower heritability estimates varying between 0.30 and 0.40 (Saranga et al, 2008); these estimates are thus substantially lower than the estimates in our study. Family studies, however, typically produce lower heritability estimates than twin studies, well shown for BMI (Elks et al, 2012), which may be because in family studies participants are typically measured at different ages when putative different genetic components may affect body composition as well as body shape.…”

“…Meta‐analyses of previous twin studies have shown moderate heritability estimates (ie, the proportion of total variation explained by genetic variation) for aerobic physical fitness (Schutte, Nederend, Hudziak, de Geus, & Bartels, 2016) and muscle strength‐related traits (Zempo et al, 2017). For somatotype components, moderate to high heritability estimates have been found in twin studies (Peeters et al, 2003; Peeters et al, 2007; Reis et al, 2007), whereas studies using family and pedigree designs have reported moderate heritabilities and some of them have not been able to distinguish genetic factors from other familial factors (Katzmarzyk et al, 2000; Pereira et al, 2017; Rebato, Jelenkovic, & Salces, 2007; Saranga et al, 2008). Since different models with different assumptions have been used in these studies, it is difficult to compare the heritability estimates derived from them.…”

A statistical investigation into the sharing of common genetic factors between blood pressure and obesity phenotypes in nuclear families from the Greater Bilbao (Spain)

“…Concerning anthropometric somatotype, the lowest genetic determination observed for the fatness component (endomorphy) was in the range of the previously mentioned obesity phenotypes. The lack of congruence between the published studies in defining which somatotype component is more heritable results in different patterns of heritability among the populations [19,[41][42][43].…”

Comparison of Somatotype of Physically Active Punjabi Men of different Age Group

“…Endomorphy is the relative fatness, mesomorphy is the relative musculo-skeletal robustness and ectomorphy is the relative linearity or slenderness (Heath & Carter, 2002). There are many factors like gender, genetics, feeding habits and environment that affect human shape and size (Saranga et al, 2008;Reis et al, 2007). Somatotype is also seen to vary with change in physical activity as well.…”